| 摘要 |
<p>A hydraulic valve assembly (10) for selectably delivering hydraulic fluid fr om a supply of hydraulic fluid to one of a first hydraulic operator (80) and a second hydraulic operator (82) is disclosed. The assembly includes first (32 ) and second (34) supply ports which communicate with the supply (18) and four operator ports (44,46,48,50). First (44) and third (48) ports communicate wi th the first hydraulic operator (80). Second (46) and fourth (50) ports communicate with the fourth hydraulic operator (82). First (36) and second (38) chambers are provided. The first chamber communicates with the first supply port and first and second operator ports. The second chamber communicates with the second supply port and third and fourth operator ports . Two selection valves (60,61) operating in unison are each located in each chamber. The selection valves operate between a first position at a first hydraulic fluid pressure and a second position at a second hydraulic fluid pressure. In a first position, the valves permit fluid communication of the first and second supply ports with the first and third operator ports, respectively. In a second position, the valves permit fluid communication wi th the second and fourth operator ports.</p> |
